Undergrate draft blower



Nov. 6, 1928. 1,690,112

' H. C. HOOK UNDERGRATE DRAFT BLOWER Filed June 13, 1927 2 Sheets-Sheet l gnuento'o My 6 W 33, WTW/ Patented Nov. 6, 1928.

UNITED STATES PATENT-OFFICE.

INDY C. HQQK, OI BRIDGEPOBT, CONHECTICUT; ASSIGNQB TO INTERNATIONAT. FUEL SERVICE; CORPORATION, OF BRIDGEPORT, CONNECTICUT.

N E BAT DRAFT Brownie.

Application filed June 13,

My invention relates to a fan blower, and moreparticularly to a fan blower adapted to be used as an under grate draft blower for a heating system. V Theffans and motors used for creating a draft in it heating system are usually mount-- t ed closely adjacent the ashpit or connected totthe fire boxunder the grate where they are in contact with dust from the furnace, which is largely composed of carbon. The dust worksinto the motor and not only wearsout the bearings rapidly, but being carbon in Working in between thefield and the rotor is uite aptto produce a short circuit and'cause' tliel motor to burn out. As an object of my imrentioml contemplate an arrangement of the motor and the tan" blower inwhich dust is prevented from penetratin the m0t0r,'and

7 he wear and danger caused therebyelimi- 29 n ed,

' There is eensiderable danger in using motors; closely adjacent the ash pit of a furnace or heater from water accumulating in the basement in which the heater i placed. This danger not Only f om water directly penetrating the motor, but also if the motor is near a damp or wet basement floor, the vapor arising from the floor is apt to condense 1n and on the motor. As an additional object so of my invention, I contemplate a mounting a for themotor and, fan wherein the are carried in an elevated position out o reach of any water whichkmay accumulate around the heater. v I In order that the motor may not become Ov r-heated when use, it is generally considered necessary to ventilate the lmotor housing As a further object of my invention, I

' contemplate a means for ventilating a motor housingwhen sed with a fan blower in which thereis no danger of dust or other foreign matter entering the housing and damaging the parts of the motor.

To these and other ends, t e invention consistsiin the novel, features and combination of parts to be hereinafter de cribed and claimed.

' I hefdrw ngs v Fig, 1 is a side View, partially in section, of a furnace showing a preferred embodime it of my under grate draftblower mount di arse;

Fig. 21s a 1 ser es wi h l nview or the. motor and scr en, removed; an i 1927. Serial No. 198,518.

Fig. 3 is an elevational View, in section, 1

showing the interior arrangement of the mo tor and fan casing.

Referring to the drawings in which I have shown a preferred embodiment of my inyention, the reference numeral 1 indicates a furnace having at the bottomthereof an ash pit 5, and secured at the rear of the ash pit around an opening formed thereinis a pipe 6, having mounted thereon an elbow 7 with my l l w gg l lii ly designated by thev reference numeral 8, mounted onthe upper end thereof. The draft blower consists of a fan casing 9 having mounted thereon an electric motor 10, which is preferably a'uniersal variable speed motor adapted for either alternating or direct current. The motor 10 consists of a two-part casing 11 and 12, secured together in any suitable manner,

and on an intermediate portion of part 12 and extending radially therefrom arev legs "13; 14 and 15, securedon the upper end of the casing 8 by means of cap screws 16, 17 and 18. WVithin the motor casing part '11 is a field magnet 19, surrounding anarmature 20,

mounted on ashaft 21, supported in bearings i and above the throat the wall of the casing tapers outwardly, as shown at 28. Mounted on thelower end ofshaft 21 is a fan'29,

having outwardly and upwardly extending blades .30, the outer ends of whichareopposite the throat 27. The motor casing'part 12 is spaced from the upper end of the tapered wall Y28, and has an inwardly and downwardly tapering wall" spaced. inwardly from the fan casing and forming with the wall 28 an intake for, the fan 29. Below the fan 29 and formed'integrally with the casing 9 are a series of radial fins 32 for a purpose to be hereinafter described. if

Mounted on theupper surface 33 of th'e'casing 9 is a screen 34having its lower edge 85 resting on the upper edge 33 of the casing ,9, the upper end of the screen 3&1 close-1y embracing, t e m tor 1.0, A series of wedge members 36 are carried within the screen 34, each of the wedges having one of its ends in contact with a portion of the inner wall of the screen at the lower end thereof, and its upper end in contact with a portion of the motor wall which is tapered inwardly slightly at this point, as indicated by the reference numeral 37. The motor casing 10, below the field 19, is connected to the intake of the fan chamber by a series of openings 38.

On the top of the motor 10 in the part 11, covering the bearing 23, and rendering the motor casing dust-tight at this point, is a hollow cap 239, having a plug in the upper portion thereof. In the lower end of motor casing part 12, and above the bearing 22, is a grease or oil chamber 41, having a cover 42; and connected to the chamber 41, by means of a pipe 4-3, is a grease or oil cup 41. The brushes 25 are carried in tubes 45, mounted in bushings 16, fixed in the motor casing, and are urged againstthe commutator-2a by springs 14.7, the outer ends of which are supported by caps 48 which, in conjunction with bushings -16, render the motor casing dusttight. Below the bearings 22 and 23 are grease or oil traps l9 and which prevent the entry of oil into the motor 10 and the fan casing 9, respectively.

In operation, it will be understood that electric current, either alternating or direct, may be supplied to the motor and, if desired, may be controlled by a thermostatically operated switch inserted in the heater and wired in series with the motor. Upon rotation of the shaft 21, and the fan 29 carried thereon, air is drawn through the screen 34 downwardly between the walls of the fan casing E) and the tapered surface of the motor casing part 12 by the fan 29. The air discharged by the fan passes between the fins 32 arranged therebelow, which prevent rotary movement of the air passing through the draft blower. All of, the parts of the motor casing above the screen 3a are air and dust-tight, and no dust can penetrate the motor above this point. The openings 38 in the lower part of the motor casing permit the casing to be ventilated and cooled. Since the air passing to the rotary fan is drawn by these openings, there is a tendency for the air to entrain other air from the motor casing and 'prevent dust from entering through the openings in the latter. In addition, these openings being carried in an under surface of the motor casing, there is no tendency for dust to settle therein while the motor is idle. By means of the wedges 36, the screen may be detachably secured on the fan housing, the tapered portion 37 of the motor casing 10 cooperating with the upper edge of the wedges to secure them tightly in place. The provision of an upwardly extending connection between the draft blower and the ash pit permits the motor to be carried in an elevated position where it may not readily come in contact with any water accumulating in the basement and is not likely to be endangered by an tl(,'(!l(l(i'll:li blow.

\Vhile. I have shown and described a preferred embodiment of my invention, it will be understood that the same not to be limited to all the details shown but is capable of modification and variation within the spirit of the invention and the scope of the appended claims.

\Vhat I claim is 1. Ina draft blower, a vertical fan casing. a. vertical motor mounted on said casing, and having a rotary shaft extending downwardly into said fan casing, a fan on said shaft and within said casing, a screen between said motor and said casing, said motor being part- 1y carried within but spaced from said casing to provide an intake for said fan, the motor casing above said screen being dust-tight, and said motor casing being provided with openings therein below said screen and within said fan casing.

2. In a draft blower, a vertical fan casii'ig. a vertical motor mounted on said casing, said motor having a casing and a rotary shaft extending downwardly into said fan casing, a fan on said shaft, said motor (JilSlIlQ' having an outwardly and upwardly tapering side wall above said fan, said motor casing having its lower end received within the casing, and said motor casings being provided with open ings leading from the interior of said fan easing into the interior of said motor.

3. In a draft blower, a vertical fan casing. a vertical motor mounted on said casing and having a casing and a rotary shaft extending downwardly into said fan casing, a fan on said shaft, said motor casing having an outwardly and upwardly tapering side wall above said fan. said motor casing having its lower end received within the casing, said lower end having an upwardly and outwardly tapering wall, and said motor casing being provided with openings in said ta peringlower end leading from the interior of said 1 an casing into said motor casing, and a screen between the upper end of said fan casing, and said motor casing, said screen being detach ably secured on said fan casing.

4. In a draft blower, a. vertical fan casing and a vertical motor supported on the upper edge of the fan casing and extending partly into said casing, the exterior walls of said motor being spaced from the interior walls of the fan casing, and the motor wall being provided with ventilating openings in an under portion thereof, the motor above said openings being dust'tight.

5. In a draft blower, a vertical fan casing and a vertical motor supported on the upper edge of the fan casing and extending partly into said casing, the exterior walls of said motor being spaced from the interior walls of the fan casing, and ventilating openings in an under portion of the motor Wall and within said fan casing, the motor above said openings being dusttight.

6. In a draft blower, a vertical fan casing and a vertical electric motor supported on the upper edge thereof, said motor including a casing and a field and armature within said casing, the exterior wallsof said motor being spaced from the interior walls of the fan casing, and the walls of said motor being provided with ventilating openings in an under portion thereof, said field and armature beings, and said motor casing being dust-tight above said openings. 7

7. In a draft blower, alfan casing, a motor mounted partly in and spaced from the walls of said casing at one end thereof, said casing being provided with inwardly extending lugs at said end, and said motor being provided. with radially extending legs mounted on said lugs, and a screen mounted on the end of the fan casing, said motor extending through said screen and the extending part of the motor casing being dust-tight.

In witness whereof, I have hereunto set my hand this 4th day of June, 1927.

HENRY C; HOOK. 

